I have a 1999 volvo s80 t6 with 122,000 miles. Should I seafoam the car? If so, how? I know 1/3 of the can in the fueltank. What else?

 

I put half a can in the gas tank and half in the crank 500 miles before I plan to change the oil, once or twice a year.

 

I'm pretty sure your only supposed to run the engine for like 10-15 minutes with that in there....Good idea to NOT do it like that anymore

 

It's a debatable subject. I've heard both. I have, and others I know use it the way I described for years with out any issues.

 

Pull the vaccum hose on the drivers side of the intake manifold while the engine is running. You'll need to have somebody in the car working the accelerator to keep it from stalling. I use a small funnel in the hose and slowly pour 1/3 to 1/2 of the can in. Pour fast as you can but not so fast that it stalls the engine. It'll smoke like a beast. As soon as you pour the last drop in shut off the engine. replace the vaccum hose. Let sit for 15 minutes or so. Start it up and rev the engine up and down for 5 min or so, or until the exhaust doesn't blow smoke. Mine in governed so it can't go over 4000 rpms. It'll smoke like a beast again! this cleans the intake, injectors, and decarbonizes the valves and pistons. Runs smoooooooth afterwards.

Also, I put 1/3 can in my oil with 140K on my car. Left it in for two 500 plus mile trips then changed my oil. It helped clean up my pcv a bit too!